Roads became rivers across Helensburgh and Lomond at the weekend as nearly a month's worth of rain fell in 24 hours.
Ten people were airlifted to safety from A83 on Saturday as seven landslips hit the route.
Sandbags were used in the centre of Helensburgh to try to protect businessses and were still visible at some doors by Monday.
There were dozens of flood warnings across the region as rail lines disappeared under water and transport was nearly impossible in many directions.
As well as the A83 being closed, the A82 was impacted along with many local roads. From Cardross to the Churchill estate to Rhu to Arrochar and Tarbet, the flooding was widespread.
Water was seen pouring from a manhole cover in both Churchill and Cardross, as well as covering the full width of some roads in Helensburgh, Rhu, Shandon and on rural routes.
Businesses and campaigners were particularly alarmed by how overwhelmed the sewer system was with the volume of water.
And projections for rising mean sea levels within the decade mean both mitigation and adaptation will need to be a focus.
By Monday afternoon, around 9,500 tonnes of debris had been removed from the A83 trunk road. The landslips would not have been prevented by the £1/2 billion plan for an open-sided tunnel at the Rest and Be Thankful.
Angela Anderson, lead for Plastic Free Helennsburgh, said she tried to get a resilience planning meeting in Cove and saw quite a few vans and cars damaged by items hidden by the flood water. She also saw a couple clearning drains at the end of West Montrose Street.
She said: "Notably the tide was well out, the sea was the colour of coffee icing and you could see the burns pouring in above the level of the sea.
"We have had a number of heavy rain episodes in the past few weeks. Gravel is being washed out and making rapid transit especially where verges are now paved. Leaves are falling and being torn down.
"Water had been spouting up through road drains, up, down and across the town. There is no resource to clean drains in reponse to heavy rain or blokages across the town, nevermind all of Argyll.
"If the drains were clear and the combined sewer overflow opened for emergency discharge, most of the water would drain when the tide is out.
"However, the rate of flow needs to be slowed to prevent flooding not accelerated.
"I hope everyone is ok and I'm glad the decision to cancel trains came early. A community response to gutter cleaning might be part of a place for community resilience."
Estimates by Climate Central in 2018 projected mean high tides and coastal flooding risks around the UK.
Ms Anderson said it does not include storm levels, and the more area paved over in private or public properties, the more water has nowhere to go. And it moves faster.
She said they have been putting in planning objections to increases in hard surfaces.
"People should recognise there's potentially a local problem with rising seas, not just something that happens in the Maldives," she said before Saturday's flooding.
"There are mitigation measures that can be done locally. There's a big risk of flooding.
"There's plenty of evidence that we do get floding here and flooding is likely to get worse.
"The map shows mean high tide permanently. For every centimeter that rises, it's exacerbated with storms."
According to projections, the entire Clydeside faces risk by 2030 - and it gets worse as the decades progress.
Helensburgh Leisure Centre and that land was raised to 5.4m when it was built, a level that would protect it and a fraction of West Clyde Street.
The rest of the street and its businesses are shown as at risk - and pictures from the weekend showed far more of the town impacted.
Further up the Clyde, Hermitage Academy and Morrisons are both face being below flood level, and a long stretch of the rail line south-east of Craigendoran is underwater.
There was flooding on Saturday behind the school.
Most of the A814 from Helensburgh, through Rhu and past the Faslane Peace Camp is all at risk.
Wendy Hamilton, owner of Grasshopper Toys on West Princes Street and representative of the Federation of Small Business, said: "The flooding of Helensburgh town centre over the past weekend was extraordinary to witness and whilst the volume of rain falling on our town was exceptional, it was alarming to see the town’s drainage system being overwhelmed so quickly.
"The road on East Princes Street turned into a river with drains failing to clear the deluge. As a result, shops on East Princes street were repeatedly flooded as cars passed by, driving water from the flooded street into the shop premises.
"On East Clyde Street the road was impassable for sections and some shops and homes resorted to sand bags at their entrances in an attempt to hold the water at bay.
"Further up Sinclair street at the junction with Queen Street water was literally bubbling out of the drainage covers, the drains were overwhelmed.
"Whilst the weekend’s weather was unusually intense, it’s not the first time the town has suffered from heavy rainfall and flooding and it won’t be the last time.
"We cannot expect home owners and businesses to bear the costs of an inadequate or poorly maintained drainage system, if improvements can be made.
"We need to ask the council what maintenance, if any, is being done to our town’s drainage system and what improvements we can expect going forward."
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